SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Advertising cost	$ 78,000,000	$ 38,000,000	$ 18,000,000
Summary of Significant Accounting Policies [Line Items]
Equity method investments carrying value	$ 141,000,000	$ 521,000,000
Percentage of net revenues	100.00%	100.00%	100.00%
Share of equity earnings from investments in affiliates	$ 78,000,000	$ 75,000,000	$ 57,000,000
Percentage of net accounts receivable	100.00%	100.00%
Operating income (loss)	$ 2,381,000,000	$ 1,971,000,000	1,231,000,000
Net income	2,080,000,000	1,499,000,000	906,000,000
Trading equity securities gain or (loss)	56,000,000	8,000,000	10,000,000
Trading securities	121,000,000
Impairment charges	0	0	$ 0
Equity Securities without readily determinable fair value	4,000,000	25,000,000
Available-for-sale debt securities	1,000,000	12,000,000
Operating lease right-of-use assets	597,000,000	604,000,000
Operating lease, liability	645,000,000
Recurring Basis
Summary of Significant Accounting Policies [Line Items]
Available-for-sale debt securities	1,000,000	12,000,000
Equity investments	44,000,000
Deferred compensation trading securities	77,000,000	67,000,000
Other Assets
Summary of Significant Accounting Policies [Line Items]
Trading securities		$ 67,000,000
Other Assets | Recurring Basis
Summary of Significant Accounting Policies [Line Items]
Deferred compensation trading securities	77,000,000
Prepaid Expenses and Other Current Assets | Recurring Basis
Summary of Significant Accounting Policies [Line Items]
Equity investments	$ 44,000,000
DIS business
Summary of Significant Accounting Policies [Line Items]
Percentage of net revenues	97.00%	97.00%	96.00%
Percentage of net accounts receivable	97.00%	97.00%
Operating income (loss)	$ 2,646,000,000	$ 2,201,000,000	$ 1,298,000,000
DIS business | Government payers
Summary of Significant Accounting Policies [Line Items]
Percentage of net revenues	10.00%	11.00%	15.00%
Percentage of net accounts receivable	6.00%	6.00%
DIS business | Patients
Summary of Significant Accounting Policies [Line Items]
Percentage of net revenues	12.00%	11.00%	13.00%
Percentage of net accounts receivable	21.00%	11.00%
Minimum
Summary of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%
Finite-lived intangible asset, useful life	5 years
Minimum | Laboratory Equipment and Furniture and Fixtures
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Minimum | Software and Software Development Costs
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	5 years
Minimum | DIS business
Summary of Significant Accounting Policies [Line Items]
Percentage of net revenues	95.00%	95.00%	95.00%
Maximum
Summary of Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	49.00%
Finite-lived intangible asset, useful life	20 years
Maximum | Building and Building Improvements
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	31 years 6 months
Maximum | Laboratory Equipment and Furniture and Fixtures
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	12 years
Maximum | Software and Software Development Costs
Summary of Significant Accounting Policies [Line Items]
Property, plant and equipment, useful life	10 years